Accumulating evidence supports the importance of chronic stress in the development of cardiovascular disease (CVD). One of the most consistent set of findings in this literature is the research on occupational stress. A growing literature is consistent with the job strain model, showing that chronic exposure to highly demanding and uncontrollable work environments may be linked with the development of clinical CVD as well as subclinical atherosclerosis. Much remains to be understood, however, about the potential mechanisms linking occupational stress and CVD, and the degree to which such mechanisms are specific to the workplace. For example, one assumption of the job strain model is that moment-to-moment behavioral processes account for the effects of occupational stress on health. This assumption is difficult to test using standard methodologies. We have recently developed state-of-the art computer-assisted ambulatory assessment procedures that allow us to capture the psychological and biological markers of mental stress over the course of daily life. Use of these procedures will allow us to examine, more precisely than has previously been possible, the mechanisms accounting for the health effects of occupational stress. 530 healthy employees (ages 30-55) will be administered ambulatory blood pressure (ABP) and electronic diary assessments over three working days and one nonworking (weekend) day. Global assessments of occupational stress will also be employed, along with risk factors and biomarkers for CVD, including ultrasound measures of carotid artery atherosclerosis. We will examine the role of daily psychosocial strain, as assessed in real time in the natural environment, in explaining the association between occupational stress and CVD biomarkers. Both biological factors (hemodynamic and neuroendocrine factors) and health risk behaviors will be examined as potential mechanisms accounting for these effects, models that have been hypothesized but never explicitly tested. The role of daily demands outside of the workplace in contributing to the effects of occupational stress will be characterized, and the patterns of daily living accounting for sex differences in the relationship between occupational stress and biomarkers for CVD will also be examined.